Applied patch from David Douthitt to re-add -print option to find.
[oweals/busybox.git] / findutils / grep.c
1 /*
2  * Mini grep implementation for busybox using libc regex.
3  *
4  * Copyright (C) 1999,2000,2001 by Lineo, inc.
5  * Written by Mark Whitley <markw@lineo.com>, <markw@codepoet.org>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20  *
21  */
22
23 #include <stdio.h>
24 #include <stdlib.h>
25 #include <getopt.h>
26 #include <regex.h>
27 #include <string.h> /* for strerror() */
28 #include <errno.h>
29 #include "busybox.h"
30
31
32 extern int optind; /* in unistd.h */
33 extern int errno;  /* for use with strerror() */
34 extern void xregcomp(regex_t *preg, const char *regex, int cflags); /* in busybox.h */
35
36 /* options */
37 static int ignore_case       = 0;
38 static int print_filename    = 0;
39 static int print_line_num    = 0;
40 static int print_count_only  = 0;
41 static int be_quiet          = 0;
42 static int invert_search     = 0;
43 static int suppress_err_msgs = 0;
44
45 #ifdef BB_FEATURE_GREP_CONTEXT
46 extern char *optarg; /* in getopt.h */
47 static int lines_before      = 0;
48 static int lines_after       = 0;
49 static char **before_buf     = NULL;
50 static int last_line_printed = 0;
51 #endif /* BB_FEATURE_GREP_CONTEXT */
52
53 /* globals used internally */
54 static regex_t regex; /* storage space for compiled regular expression */
55 static int matched; /* keeps track of whether we ever matched */
56 static char *cur_file = NULL; /* the current file we are reading */
57
58 static void print_line(const char *line, int linenum, char decoration)
59 {
60 #ifdef BB_FEATURE_GREP_CONTEXT
61         /* possibly print the little '--' seperator */
62         if (last_line_printed && last_line_printed < linenum - 1) {
63                 puts("--");
64         }
65         last_line_printed = linenum;
66 #endif
67         if (print_filename)
68                 printf("%s%c", cur_file, decoration);
69         if (print_line_num)
70                 printf("%i%c", linenum, decoration);
71         puts(line);
72 }
73
74 static void grep_file(FILE *file)
75 {
76         char *line = NULL;
77         int ret;
78         int linenum = 0;
79         int nmatches = 0;
80 #ifdef BB_FEATURE_GREP_CONTEXT
81         int print_n_lines_after = 0;
82         int curpos = 0; /* track where we are in the circular 'before' buffer */
83         int idx = 0; /* used for iteration through the circular buffer */
84 #endif /* BB_FEATURE_GREP_CONTEXT */ 
85
86         while ((line = get_line_from_file(file)) != NULL) {
87                 chomp(line);
88                 linenum++;
89
90                 /*
91                  * test for a postitive-assertion match (regexec returns success (0)
92                  * and the user did not specify invert search), or a negative-assertion
93                  * match (regexec returns failure (REG_NOMATCH) and the user specified
94                  * invert search)
95                  */
96                 ret = regexec(&regex, line, 0, NULL, 0);
97                 if ((ret == 0 && !invert_search) || (ret == REG_NOMATCH && invert_search)) {
98
99                         /* if we found a match but were told to be quiet, stop here and
100                          * return success */
101                         if (be_quiet) {
102                                 regfree(&regex);
103                                 exit(0);
104                         }
105
106                         /* otherwise, keep track of matches and print the matched line */
107                         nmatches++;
108                         if (!print_count_only) {
109 #ifdef BB_FEATURE_GREP_CONTEXT
110                                 int prevpos = (curpos == 0) ? lines_before - 1 : curpos - 1;
111
112                                 /* if we were told to print 'before' lines and there is at least
113                                  * one line in the circular buffer, print them */
114                                 if (lines_before && before_buf[prevpos] != NULL)
115                                 {
116                                         int first_buf_entry_line_num = linenum - lines_before;
117
118                                         /* advance to the first entry in the circular buffer, and
119                                          * figure out the line number is of the first line in the
120                                          * buffer */
121                                         idx = curpos;
122                                         while (before_buf[idx] == NULL) {
123                                                 idx = (idx + 1) % lines_before;
124                                                 first_buf_entry_line_num++;
125                                         }
126
127                                         /* now print each line in the buffer, clearing them as we go */
128                                         while (before_buf[idx] != NULL) {
129                                                 print_line(before_buf[idx], first_buf_entry_line_num, '-');
130                                                 free(before_buf[idx]);
131                                                 before_buf[idx] = NULL;
132                                                 idx = (idx + 1) % lines_before;
133                                                 first_buf_entry_line_num++;
134                                         }
135
136                                 }
137
138                                 /* make a note that we need to print 'after' lines */
139                                 print_n_lines_after = lines_after;
140 #endif /* BB_FEATURE_GREP_CONTEXT */ 
141                                 print_line(line, linenum, ':');
142                         }
143                 }
144 #ifdef BB_FEATURE_GREP_CONTEXT
145                 else { /* no match */
146                         /* Add the line to the circular 'before' buffer */
147                         if(lines_before)
148                         {
149                                 if(before_buf[curpos])
150                                         free(before_buf[curpos]);
151                                 before_buf[curpos] = strdup(line);
152                                 curpos = (curpos + 1) % lines_before;
153                         }
154                 }
155
156                 /* if we need to print some context lines after the last match, do so */
157                 if (print_n_lines_after && (last_line_printed != linenum)) {
158                         print_line(line, linenum, '-');
159                         print_n_lines_after--;
160                 }
161 #endif /* BB_FEATURE_GREP_CONTEXT */ 
162                 free(line);
163         }
164
165         /* special-case post processing */
166         if (print_count_only) {
167                 if (print_filename)
168                         printf("%s:", cur_file);
169                 printf("%i\n", nmatches);
170         }
171
172         /* remember if we matched */
173         if (nmatches != 0)
174                 matched = 1;
175 }
176
177 extern int grep_main(int argc, char **argv)
178 {
179         int opt;
180         int reflags;
181 #ifdef BB_FEATURE_GREP_CONTEXT
182         char *junk;
183 #endif
184
185         /* do normal option parsing */
186         while ((opt = getopt(argc, argv, "iHhnqvsc"
187 #ifdef BB_FEATURE_GREP_CONTEXT
188 "A:B:C:"
189 #endif
190 )) > 0) {
191                 switch (opt) {
192                         case 'i':
193                                 ignore_case++;
194                                 break;
195                         case 'H':
196                                 print_filename++;
197                                 break;
198                         case 'h':
199                                 print_filename--;
200                                 break;
201                         case 'n':
202                                 print_line_num++;
203                                 break;
204                         case 'q':
205                                 be_quiet++;
206                                 break;
207                         case 'v':
208                                 invert_search++;
209                                 break;
210                         case 's':
211                                 suppress_err_msgs++;
212                                 break;
213                         case 'c':
214                                 print_count_only++;
215                                 break;
216 #ifdef BB_FEATURE_GREP_CONTEXT
217                         case 'A':
218                                 lines_after = strtoul(optarg, &junk, 10);
219                                 if(*junk != '\0')
220                                         error_msg_and_die("invalid context length argument");
221                                 break;
222                         case 'B':
223                                 lines_before = strtoul(optarg, &junk, 10);
224                                 if(*junk != '\0')
225                                         error_msg_and_die("invalid context length argument");
226                                 before_buf = (char **)calloc(lines_before, sizeof(char *));
227                                 break;
228                         case 'C':
229                                 lines_after = lines_before = strtoul(optarg, &junk, 10);
230                                 if(*junk != '\0')
231                                         error_msg_and_die("invalid context length argument");
232                                 before_buf = (char **)calloc(lines_before, sizeof(char *));
233                                 break;
234 #endif /* BB_FEATURE_GREP_CONTEXT */
235                 }
236         }
237
238         /* argv[optind] should be the regex pattern; no pattern, no worky */
239         if (argv[optind] == NULL)
240                 show_usage();
241
242         /* sanity check */
243         if (print_count_only || be_quiet) {
244                 print_line_num = 0;
245 #ifdef BB_FEATURE_GREP_CONTEXT
246                 lines_before = 0;
247                 lines_after = 0;
248 #endif
249         }
250
251         /* compile the regular expression
252          * we're not going to mess with sub-expressions, and we need to
253          * treat newlines right. */
254         reflags = REG_NOSUB; 
255         if (ignore_case)
256                 reflags |= REG_ICASE;
257         xregcomp(&regex, argv[optind], reflags);
258
259         /* argv[(optind+1)..(argc-1)] should be names of file to grep through. If
260          * there is more than one file to grep, we will print the filenames */
261         if ((argc-1) - (optind+1) > 0)
262                 print_filename++;
263
264         /* If no files were specified, or '-' was specified, take input from
265          * stdin. Otherwise, we grep through all the files specified. */
266         if (argv[optind+1] == NULL || (strcmp(argv[optind+1], "-") == 0)) {
267                 grep_file(stdin);
268         }
269         else {
270                 int i;
271                 FILE *file;
272                 for (i = optind + 1; i < argc; i++) {
273                         cur_file = argv[i];
274                         file = fopen(cur_file, "r");
275                         if (file == NULL) {
276                                 if (!suppress_err_msgs)
277                                         perror_msg("%s", cur_file);
278                         }
279                         else {
280                                 grep_file(file);
281                                 fclose(file);
282                         }
283                 }
284         }
285
286         regfree(&regex);
287
288         return !matched; /* invert return value 0 = success, 1 = failed */
289 }